An improved official test for car fuel economy was introduced in September 2017.

The new WLTP test gives figures closer to a car's "true mpg" than the pre-2017 NEDC test, which tended to overstate mpg compared to what real-world drivers would get.

When looking at mpg for two cars, always check the figures were measured under the same test system. Comparing one car's WLTP figure with another's NEDC figure will not tell you which has the better mpg.